When I spoke to Terry Pelz late yesterday afternoon, he sounded hoarse and exhausted. "I'm just about talked out," he said.

Pelz is a former prison warden at the Darrington Unit who now runs a criminal justice consulting firm in Missouri City, about 20 miles southwest of Houston. He's been in high demand the past couple days, as an expert on the Aryan Brotherhood of Texas. The ABT are being eyed as possible suspects in the killing of Kaufman County DA Mike McLelland, his wife Cynthia and assistant DA Mark Hasse. The group is, as we outlined yesterday, a violent and growing criminal enterprise throughout the state and especially in north Texas.

Pelz has plenty of direct experience with the ABT. Over his 21 years in the TDCJ system, he says, "I was witnessing their growth. I had a lot of them locked up in Darrington. They knew me."

Being known by the ABT apparently means being threatened frequently by them, as Pelz discovered. He received a number of verbal and written threats over the years.

"You just take 'em with a grain of salt," he says. You know, "'I'm gonna kill you and your family when I get out' and all that garbage."

Although Pelz certainly sees the ABT as a violent and not particularly pleasant group of people, something doesn't sit right with him in the McLelland and Hasse killings.

"That'd be a big leap for them," he says. "I just don't think it's credible that it's them."

Why is the ABT the focus of so much speculation in these murders to begin with? A couple reasons. As The Dallas Morning News' Tanya Eiserer wrote in February, after Hasse's killing, the Texas Department of Public Safety issued a bulletin in December, warning that they had "credible information" that the ABT was planning retaliatory attacks on law enforcement officers, after the massive federal indictment that netted 34 of their members, including five high-ranking "generals." (Yesterday, a Houston federal prosecutor involved in that case quietly withdrew from it, prompting speculation that he was afraid for his family's safety).

In Kaufman County, McLelland himself had gone after the ABT aggressively. In August, he secured a conviction against James Patrick Crawford, a reputed ABT member on trial for aggravated kidnapping, aggravated assault, directing gang activities, possession of a controlled substance with intent to deliver and engaging in organized criminal activity. Crawford, as the Kaufman Herald noted at the time, was the first gang member to be prosecuted in the county under a newish section of the Texas Penal Code, which in 2009 added penalties for directing criminal street gangs. Crawford got two life sentences.

"I'm just ecstatic about the sentences," McLelland told the Herald at the time. "It shows that those people can't come down here and run roughshod over folks in Kaufman County."

But in the Kaufman County murders, Pelz says, "It's just not their style. I studied them for almost 30 years. Like all prison gangs, they make threats on public officials, but I've never seen them carry them out."

Why not? Well, Pelz says, after a moment of reflection, "You're dealing with a bunch of dumb ol' white boys who are meth cookers."

Mark Potok of the Southern Poverty Law Center, a former journalist who's also studied the ABT, agrees that if the gang is involved, it would be an unprecedented move for them.

"I wouldn't say [the murders] look like anything we've seen before from the ABT," he says. "If in fact this is them, it would be an astounding kind of move to make."

He points out that only about 20 prosecutors in the U.S. have been murdered over the course of the entire 20th century. "It's an incredibly rare phenomenon. And I've never heard of any prison gang assassinating correctional officials," other than the occasional prison guard.

Potok, who lived in Dallas for a time and did some work in East Texas, also found, like Pelz, that meth has thoroughly permeated the ABT. "That's probably their number one thing," he says.

It's been suggested that the ABT could be connected with the killing of Colorado prisons head Tom Clements through the drug trade; the prime suspect in the Clements killing, Evan Ebel, was a reputed member of a white power gang called 211 Crew that also has a taste for meth.

"We know 211 Crew is also involved in the drug trade," Potok says. But he sounds skeptical. "How that relates, I don't know. It's conceivable that in some way these groups are working together. I'm not suggesting that's true or that I even think that's true. It seems hard to believe, frankly."

Pelz and Potok also differ on how dangerous the ABT actually is. In a CNN interview, Potok called the ABT "arguably the most violent white supremacist prison gang out there."

"I totally disagree with that," Pelz says bluntly. "I think the California Aryan Brotherhood and the [Nazi] Low Riders in California and around the nation are far more violent than the ABT. I don't know what he bases that on. I think he bases a lot of that on the problems they've had within the gang." As Pelz puts it, the ABT has been "cleaning house for the last couple years, getting rid of members who aren't doing what they're supposed to do."

That housecleaning sometimes involves murder, Pelz acknowledges. But he speculates that the murders in Kaufman County -- and he's quick to note that this is only speculation -- have something to do instead with the ABT's growing relationship with Mexican drug cartels, who have bonded across racial lines over their shared love of selling meth.

Pelz puts his money on a partnership between the ABT and the cartels that's soured. "Something was disrupted and somebody got pissed off in the cartel, I think," he says. "And they got one of their associates to take care of business. I just don't think the ABT was directly involved in it."

Drug cartels have certainly assassinated law enforcement officials before, although in Mexico, not the United States. In 2008, the police chief of Mexico City, Edgar Eusebio Millán Gómez, who had been aggressively pursuing the cartels, was shot dead outside his home. The same year, three other Mexico City police officials were also killed. The Texas Department of Public Safety has warned that cartel members along the border are becoming "increasingly confrontational" in their encounters with law enforcement. A huge AP story released this week suggests that the cartels may be moving further into the U.S., cutting out American middleman drug traffickers they've long relied upon.

All that is a long way from Kaufman County, though, where the ABT is undoubtedly active. One thing both Potok and Pelz can agree on: If this is a war the ABT has launched against law enforcement, it's unlikely to end well for the gang.

"If the ABT is involved in murdering prosecutors one after another, they're going to be destroyed," Potok says. "The weight of the state is going to come down on them like a thousand tons of bricks. If they're going to pick off prosecutors, they're starting a war they will not win."